论文标题
近场显微镜中非本地电导率的特征
Signatures of non-local conductivity in near-field microscopy
论文作者
论文摘要
我们提出和理论上证实了一种使用近场显微镜工具研究二维电子系统（2DE）的非本地电导率的新方法。我们表明，对于2DES中各种电荷载体的诱导偶极矩照明近场探针的高度依赖性大不相同。对于流体动力运输方式，诱导的偶极矩鳞片为$ z_0^{ - 2} $，其中$ z_0 $是探针高度以上的探针。对于Drude和经典的传导机制，偶极力矩均匀地缩放为$ Z_0^{ - 3} $。在前一种情况下，偶极矩是载体密度无关的，而在后者中，偶极矩很大程度上取决于载体密度。更普遍地，我们发现探针的诱导偶极矩与波矢依赖的电导率的拉普拉斯变换成正比，而2DES在波矢量上的旋转函数和反向电位函数成正比。我们的结果应该为研究固体中非本地电导率的研究提供一个简单的工具，这是在其他技术方面具有挑战性的。
We propose and theoretically substantiate a new method to study the non-local conductivity of two-dimensional electron systems (2DES) using the tools of near-field microscopy. We show that the height dependence of induced dipole moment of illuminated near-field probe is substantially different for various transport regimes of charge carriers in 2DES. For hydrodynamic transport regime, the induced dipole moment scales as $z_0^{-2}$, where $z_0$ is the elevation of probe above the 2DES. Both for Drude and classical ballistic regimes of conduction, the dipole moment scales as $z_0^{-3}$. In the former case, the dipole moment is carrier density-independent, while in the latter it largely depends on carrier density. More generally, we find that the induced dipole moment of the probe is proportional to the Laplace transform of wave-vector dependent conductivity and inverse dielectric function of 2DES over the wave vectors $q$. Our results should provide a simple tool for studies of non-local conductivity in solids that was challenging to address with other techniques.
